Floor guy says GLUE. I wanted FLOAT. Which best for concrete slab?
Mittens Cat
4 years ago
Featured Answer
Sort by:Oldest
Comments (50)
Related Discussions
Which insulation underneath floor heating for Concrete slabs?
Comments (6)I am absolutely NOT an expert in this, but I can tell you our situation. First, we have concrete, too, but not on grade (3rd floor apartment). We also used heating mats, choosing Warmly Yours. (This decision involved the claims of electromagnetic fields reduction by someone else - I can't remember which one now - and coil distance and wattage per square foot.) I read a lot about trying to create a "thermal break" between the heating mat and our 12 inches of concrete. In the end, after reading a lot of posts all over the internet (reader beware, there is some pretty sketchy non-science out there), especially johnbridge and I think jcl, and after extensive discussions with my nephew who is a materials engineer, we did two things: 1/4" Wedi board and SuperTherm. Here's how we got to that decision (YMMV): So very many people told us that we didn't need any insulation, that insulation was stupid and unnecessary, that the heating mat would be absolutely fine without it. The two things we heard the most were: 1.) "I've installed 12 trillion-gazillion mats (or whatever extraordinary number they thought I would buy into), and I've never used it because you don't need it." 2.) "Heat rises." Regarding point #1, the thermal properties of wood underlayment versus concrete cannot be understated. What works over wood will be different over heat-sucking concrete. Even if you ask if all their other jobs were over wood, they very very VERY frequently lie. (Oh yeah, and I don't care what cocked-up thing you've inflicted upon other poor unsuspecting, non-researching saps....) Wood acts more as an insulator, concrete as a conductor of heat. Regarding point #2, lord this is stupid. Hot AIR rises, because it has more energy which makes the air molecules vibrate more, pushing the molecules apart, which takes up more room (for the same number of particles), which makes them less dense...so they rise above the cooler air. This is for AIR. When dealing with solids (and some liquids under some circumstances), heat acts more like electricity (both are forms of energy), and takes the path of least resistance. Meaning, that the heat from your mat will travel EITHER UP OR DOWN according to whether the concrete or your tile is more resistant to heat energy. The science behind which material involves density, heat capacity, etc. (It isn't exactly like electricity though, in that it isn't an all-or-nothing path decision. Apparently, with heat and different materials, it is a matter of what percentage - I'm over simplifying here - goes in which direction. Think about it: electrical conducting shields work absolutely, no matter how long the wire is live, but heat shielding can only slow down the transfer.) For anyone who owns a frypan with a handle that is made of a different metal than the pan body itself, this concept is in that pan. The body of the frypan is designed to transfer heat fast, the handle is made from a different metal that will absorb heat more slowly. The point: the handle WILL get hot eventually, just a matter of how much time. My nephew (a materials engineer, who doesn't work in this field but had more game than me for running the equations) figured out that my tile is waaaayyy more resistant than the concrete, that 70% of my heat would go into the concrete and only (about) 30% into the tile. All the people that said bare concrete would be "fine" were kind of technically sort of right: my tile would eventually absorb some amount of heat. I had two issues with this: how much more energy would I be paying for to heat the 12 inches of concrete AND how sloooowww would my tile heat up without insulation? So no contest, we needed a thermal break. (I wanted to be able to get my tiles warm in - at most - a couple hours. Without insulation, the mats would have to turn on about 12 hours ahead of time, just to hit 80 degrees by morning. No way.) I found a thread on johnbridge where somebody (I can't remember his screen name but I remember his real name is Eric, if that helps) actually mocked up several underlayment materials and measured how long it took for the top of the tile to move something like 20 degrees. (This was a while ago so some of these numbers might be a bit off, but the gist is the same.) So a good insulator would allow the tile to heat up faster because more heat is going up rather than down. He tested a couple products, and the clear, hands-down winner, coming in 40% less time than any of the others, was Wedi. (Interestingly, there was very little difference between the 1/4" and the 1/2". The guy that ran the test didn't understand why there wasn't a significant difference either, but we're talking about tenths-of-a-point level of small difference.) We went with 1/4" Wedi. The other thing we did - which was probably overkill - was because there are three different kinds of heat, and my nephew wanted to experiment with a ceramic (anti-reflective, anti-radiant) paint substance he read about. I understand the theory (waaayyy too involved to get into here), but the proof of this substance (SuperTherm) is not anywhere near substantiated yet. And dealing with the company sucked pretty badly (very unprofessional and difficult). But it is on half of my bath floor (we did a bunch of test to make sure it would adhere sufficiently to not screw up the tile) so I guess we'll see. The bath hasn't gone live yet and probably won't for another month. Don't let anyone tell you that you don't need it. Yes, the mat will work without insulation, but how well? How fast? (Yes, we are on a programmable timer. This was a big arguable point for the you-don't-need-no-stinkin'-insulation crowd, that the timed thermostat would cure all. That's fine as long as there are no exceptions to the original timer programming. But let me tell ya', my husband is ALL about exceptions. I swear he stays up late at night, trying to think up new ways that our routine won't suffice. He's adorable, but I need flexibility - in both lunch menus and floor temp.) I know this post is long, but your question involves some actual science (chem and physics), and knowledge is power, no matter what path you choose. And the amount of mis-information out there is staggering. And the surety with which people will tell you bad information is daunting. (And arrogant. And ignorant.)...See MoreIs floating floor on concrete slab ok, or rather have a plywood base?
Comments (3)Floating a floor over a concrete slab is very common. The things to be aware of: flatness...but this is required no matter how you install a rigid floor. Flatness doesn't matter under carpet (which is why builders LOVE to use carpet over concrete)...which is why it can take $$$$ to get a slab (that used to have carpet) ready for a rigid floor. The next thing you need to be prepared for: the cost to get the slab ready for a rigid floor (floating or otherwise). A 'nice slab' can have a price tag of $2/sf. A nasty slab can have a price of $4/sf for preparation costs (includes labout and materials). Once your slab is ready, you can lay your floor. The next thing to be aware of: underpad. Laminates and engineered hardwoods do very will with an underpad/underlayment (like cork). Vinyl does NOT like underpad. So it depends on what type of floating floor you have. And the next thing to be aware of: moisture barrier. This is required no matter how you install your floor. Floating, glue down or the questionable practice of laying plywood first and then nailing a floor to it...you will ALWAYS need a vapour barrier over concrete that is at or below 'grade' (the ground). These are all 'basic' flooring stuff. They aren't directed to a floating floor. They are required for all floors. A floating floor can have a few limits on length of run...but it depends on WHAT it is you are floating and the manufacturer's limitations. Without knowing the type of product you are installing, it is impossible to tell you what to 'look out for'....See Morewhat installation method is best for concrete slab
Comments (5)How old is the slab? How flat is the slab? What's sitting on it right now? Let's start with the basics. Old slabs (built before 1990's) can have moisture issues. Without the right adhesives (and you would be surprised at how many adhesives that say they are 'unlimited' have rather sad limitations for moisture) you can get massive failures very very quickly. I'm always surprised at the 'glue down' the plywood and then nail down the hardwood. Why not just glue down the hardwood? It requires the same adhesive...so why not go ahead and do the hardwood that way...and skip the plywood. A floating hardwood floor (with proper moisture barrier underneath) is the one least likely to fail (due to moisture). A properly prepared slab (all the grinding/filling/leveling) is going to produce a lovely floating hardwood. And if you want a 'solid' feel underneath, go ahead and use a lovely 1/4" cork underlayment underneath the hardwood (but over top the moisture barrier). It is a really nice combination....See MoreD'Vine French Oak flooring?
Comments (14)Interesting...the "Country" grade for Columbia states the knots are to be no bigger than 1.75 inches in size. Which means, had the planks with really big knots been culled, you would have received a full refund/replacement for each board that had a knot bigger than advertised. Unfortunately, in the flooring business "A floor laid is a floor paid." In other words, once it is installed there is no recourse. And I'm even sorrier to tell you that painter's tape is aggressive enough to pull up even the toughest polyurethane finish. For that reason, the blue tape is not something that should be used with floors. If anything, the yellow "sensitive surface" tape is what can be used. And even then it MUST BE removed every day...because any adhesive left long enough can pull up polyurethane. Sadly, your floor has one of the least desireable finishes: urethane acrylic. I'm not fond of it's bigger/better brother polyacrylic...I can only guess the urethane (cheaper than polyurethane) acrylic combination is less than exciting. I know you are horribly disappointed - and you should be - but there are some discussions that need to be had with the installers and the people who installed the product without knowing the specifications. I don't know who that is...but someone who was overseeing the install *should (ahem...this is rare but it is still part of the job of foreman) have known the quality of the product and the specifications. If the foreman/GC knew the knots were only supposed to be 1.75 inches in size, s/he would have known to stop work IMMEDIATELY, call the supplier/store AND THEN call you. As for the missing finish...this is not an issue with the store or the manufacturer...this is an installer issue. Whomsoever said "Ok" to blue painter's tape to be: A. Used on a polyurethane/urethane floor, and B. Allowed to sit for several days is the person who is responsible for dealing with the replacement of those planks. This is going to be a very tough lesson for someone to learn. Again, I am really sorry you went through this. It should not be like this...but it is sometimes. To get a greater sense of the quality of this product, feel free to peruse their installation/warranty paper. It is riddled with spelling and grammatical errors (in English...someone else will have to check the Spanish). https://static1.squarespace.com/static/59a8391fe3df28057d0cc72b/t/5de97cfe9b7dad66621a3762/1575582984071/D%27Vine+Eng+Installations-1204.3.pdf Even in the installation instructions it says: Stop and check everything is OK and the owner likes what is in the boxes. It says it at the top in the red box that takes up 1/4 of a page....See MoreMittens Cat
4 years agoMittens Cat
4 years agolast modified: 4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agolast modified: 4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agothinkdesignlive
4 years agothinkdesignlive
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoMittens Cat
4 years agoLynn Morford
4 years agoeverdebz
4 years agolast modified: 4 years agoMittens Cat
4 years agoLynn Morford
4 years agoMittens Cat
4 years agoLynn Morford
4 years agowacokid
4 years agoMittens Cat
3 years ago
Related Stories
![](https://st.hzcdn.com/fimgs/pictures/bathrooms/lake-district-property-james-hargreaves-bathrooms-img~86918c240368eb95_7815-1-bc147e0-w458-h268-b0-p0.jpg)
BATHROOM DESIGNWhich Flooring Should I Choose for My Bathroom?
Read this expert advice on 12 popular options to help you decide which bathroom flooring is right for you
Full Story![](https://st.hzcdn.com/fimgs/pictures/living-rooms/644-navy-st-maya-sahafi-img~3ad199e40becc0c0_6085-1-615703c-w458-h268-b0-p0.jpg)
GREEN BUILDINGConsidering Concrete Floors? 3 Green-Minded Questions to Ask
Learn what’s in your concrete and about sustainability to make a healthy choice for your home and the earth
Full Story![](https://st.hzcdn.com/fimgs/pictures/family-rooms/concrete-floored-abode-a-cabin-on-lake-wenatchee-gelotte-hommas-drivdahl-architecture-img~1241bf890ec543db_3507-1-63579fa-w458-h268-b0-p0.jpg)
REMODELING GUIDESObjects of Desire: Beautifully Individual Concrete Floors
Concrete comes in more colors and finishes than ever before. See if these 6 floors open your eyes to the possibilities
Full Story![](https://st.hzcdn.com/fimgs/pictures/kitchens/ferguson-christian-gladu-design-img~ef71ddf20ebdd085_3412-1-d52e667-w458-h268-b0-p0.jpg)
FLOORS5 Benefits to Concrete Floors for Everyday Living
Get low-maintenance home flooring that creates high impact and works with home styles from traditional to modern
Full Story![](https://st.hzcdn.com/fimgs/fb21d81e061fd7fd_2780-w458-h268-b0-p0--.jpg)
CONCRETEWhy Concrete Wants to Crack
We look at the reasons concrete has a tendency to crack — and what you can do to help control it
Full Story![](https://st.hzcdn.com/fimgs/pictures/bathrooms/markham-street-bathroom-peter-a-sellar-architectural-photographer-img~2b01b115008cb5b8_3069-1-445b3b3-w458-h268-b0-p0.jpg)
FLOORSWill Cork Float for Your Bathroom Floor?
Get the facts on advantages, disadvantages, costs and installation to see if a cork bathroom floor is right for you
Full Story![](https://st.hzcdn.com/fimgs/pictures/kitchens/elliot-road-klopper-and-davis-architects-img~8b61ce71094a21f7_5666-1-af69d48-w458-h268-b0-p0.jpg)
CONCRETEConcrete Flooring Stands Up to the Test in the Kitchen
Find out whether this durable and customizable flooring material might be right for your kitchen
Full Story![](https://st.hzcdn.com/fimgs/pictures/living-rooms/mentone-house-jasmine-mcclelland-design-img~e4c1f8f2038fbcd1_4299-1-f7f351b-w458-h268-b0-p0.jpg)
FLOORSKnow Your Flooring: Concrete
Concrete floors have a raw and elegant beauty that can be surprisingly warm
Full Story![](https://st.hzcdn.com/fimgs/a10106260e2eedf1_2751-w458-h268-b0-p0--.jpg)
REMODELING GUIDESYour Floor: An Introduction to Solid-Plank Wood Floors
Get the Pros and Cons of Oak, Ash, Pine, Maple and Solid Bamboo
Full Story![](https://st.hzcdn.com/fimgs/f5d1c15a02b1d429_1849-w458-h268-b0-p0--.jpg)
FUN HOUZZEverything I Need to Know About Decorating I Learned from Downton Abbey
Mind your manors with these 10 decorating tips from the PBS series, returning on January 5
Full Story
Daisy S